Nur al-Din Bimaristan (Arabic: البيمارستان النوري‎) is a large medieval bimaristan ("hospital") in Damascus, Syria. It is located in the al-Hariqa quarter in the old walled city, to the southwest of the Umayyad Mosque. It was built and named after the Zengid Sultan Nur ad-Din in 1154. The bimaristan is well known for its unusual portal, which displays an antique lintel and a curious flattened muqarnas vault. It is also unusual in its full-scale Mesopotamian-style muqarnas vault over the vestibule.